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Rooftop solar can cut summer peak demand by more than 50%

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Climate Progress

A new study by the Pecan Street Research Institute found that residential solar panel systems can cut electricity demand during peak summer hours by 58 percent.

The study used data gathered from Pecan Street’s demonstration project — an innovative living test lab that allows the research institute to provide original research on customer energy use, renewable energy integration and smart grid technology.

By monitoring 50 single-family homes in Austin, Texas with west- and/or south-facing solar panels from June through August this year, the study found that west-facing solar panels produced 49 percent more electricity during summer peak demand hours than south-facing panels, a finding that should make utilities think twice about excluding west-facing solar panel systems from solar rebate programs. According to the study, west-facing rooftop systems cut peak demand 65 percent, while south-facing systems reduced peak demand 54 percent.

Though west-facing systems may be better at cutting summer peak demand and add more value to the grid in certain regions, south-facing systems still have an advantage in total annual energy production — an important distinction mentioned in the report.

The Pecan Street study also looked at how much solar power was being used in the homes versus being returned to the grid. It found that during peak hours, homes used 80 percent of the solar power generated on-site, while just 20 percent was sent back to the grid. Over the course of a full day, 64 percent of the solar power generated on-site was used in the home.

Overall, the study concluded that solar panel systems can be an effective peak demand reduction tool, especially during hot summer months when utilities are trying to keep up with energy consumption.

“These findings suggest that rooftop solar systems can produce large summer peak reductions that benefit utilities and customers alike without requiring customers to change their behavior or sacrifice comfort,” said Pecan Street CEO Brewster McCracken in the report’s press release.

The Pecan Street study makes it clear that utilities have a lot to gain from rooftop solar, which isn’t the prevailing sentiment coming from the utility sector lately. Just last month, Arizona Public Service, the largest utility in Arizona, admitted that it had funded anti-solar ads during its campaign to change the state’s net metering policy.

During peak energy demand in the summer, the cost to provide electricity is extremely high and often unprofitable. By cutting summer peak demand more than 50 percent, solar panel systems offer benefits to the grid that could reduce costs for both utilities and their customers.

Mari Hernandez is a Research Associate on the Energy team at the Center for American Progress.

This article was originally published on by Climate Progress. Reproduced with permission  

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  • Matthew Wright

    It is also important to note that west facing and north facing (In Australia/Southern Hemisphere) panels installed in Queensland knock out the effects on the grid of electricity peaks that are modelled for after sundown (say 7PM) in Queensland. The reason they knock these out form a network provision and planning perspective is that the transformers can sustain a higher throughput for a limited amount of time without measurably reducing their lifespan. These are usually known as 2 hour ratings where the equipment is rated for 25% or 33% above the normal continuous nameplate rating.

    So in effect solar panels facing west and north produce at 3,4,5,5:30PM in Queensland and keep the transformers throughout the grid cool enough that they can then run 25%-33% harder for the final hour or two after sundown catering for 100% of peak events on the Queensland grid.

    Therefore from a peak generation perspective Solar PV elminiated greater than 85% of events and from a peak network provision/planning (where all the debate has been lately especially in NSW and QLD) Solar PV knocks out 100% of peak power events.

    So lets up the ante and get installing with the full support of the government and regulators!

  • azaredaniel

    “Tell the PUC: No new dirty gas plants!

    Every year, more than 70,000 California kids are rushed to the hospital because they can’t breathe, due to air pollution in Calfiornia.

    Unfortunately the Governor and the Public Utilities Commission (PUC) are considering huge new gas-fired power plants to replace the San Onofre Nuclear Generating Station. Dirty gas plants will make our air worse and just aren’t needed.

    We can’t sit by and let our air get dirtier and our kids even sicker, when we’ve got cheaper, cleaner, safer options like Renewable Energy.” Sierra Club

    California, there is enough Residential Solar to power 2.25 San Onofres, couple that with a Residential and Commercial Feed in Tariff and we can solve some of these environmental and electrical generating problems.

    The Southwest is in the midst of a record drought, some 14 years in the making, which means the water supply for many Western states – California, Arizona, Utah, Nevada – is drying up. Last month the Bureau of Reclamation announced they’re cutting the flow of water into Lake Mead, which has already lost 100 feet of water since the drought began.

    What happens if the Southwest drought does not end soon?

    Will we keep using 3 to 6 million gallons of Clean Water per Fracked well, to extract natural gas?

    This petition will ask the California Regulators and Law makers to allocate Renewable Portfolio Standards to Ca. Home Owners for a Residential Feed in Tariff, the RPS is the allocation method that is used to set aside a certain percentage of electrical generation for Renewable Energy in the the State.

    The State of California has mandated that 33% of its Energy come from Renewable Energy by 2020.

    The state currently produces about 71% of the electricity it consumes, while it imports 8% from the Pacific Northwest and 21% from the Southwest.

    This is how we generate our electricity in 2011, natural gas was burned to make 45.3% of electrical power generated in-state. Nuclear power from Diablo Canyon in San Luis Obispo County accounted for 9.15%, large hydropower 18.3%, Renewable 16.6% and coal 1.6%.

    There is 9% missing from San Onofre and with the current South Western drought, how long before the 18.3% hydro will be effected?

    Another generator of power that jumps out is natural gas, 45.3%, that is a lot of Fracked Wells poisoning our ground water, 3 to 6 million gallons of water are used per well. If Fracking is safe why did Vice Pres Cheney lobby and win Executive, Congressional, and Judicial exemptions from:

    Clean Water Act.

    Safe Drinking Water.

    Act Clean Air Act.

    Resource Conservation and Recovery Act.

    Emergency Planning Community Right to Know Act.

    National Environmental Policy Act.

    “Americans should not have to accept unsafe drinking water just because natural gas is cheaper than Coal. the Industry has used its political power to escape accountability, leaving the American people unprotected, and no Industry can claim to be part of the solution if it supports exemptions from the basic Laws designed to ensure that we have Clean Water and Clean Air” Natural Resources Defense Council.

    We have to change how we generate our electricity, with are current drought conditions and using our pure clean water for Fracking, there has to be a better way to generate electricity, and there is, a proven stimulating policy.

    The Feed in Tariff is a policy mechanism designed to accelerate investment in Renewable Energy, the California FiT allows eligible customers generators to enter into 10- 15- 20- year contracts with their utility company to sell the electricity produced by renewable energy, and guarantees that anyone who generates electricity from R E source, whether Homeowner, small business, or large utility, is able to sell that electricity. It is mandated by the State to produce 33% R E by 2020.

    FIT policies can be implemented to support all renewable technologies including:
    Wind
    Photovoltaics (PV)
    Solar thermal
    Geothermal
    Biogas
    Biomass
    Fuel cells
    Tidal and wave power.

    There is currently 3 utilities using a Commercial Feed in Tariff in California Counties, Los Angeles, Palo Alto, and Sacramento, are paying their businesses 17 cents per kilowatt hour for the Renewable Energy they generate. We can get our Law makers and Regulators to implement a Residential Feed in Tariff, to help us weather Global Warming, insulate our communities from grid failures, generate a fair revenue stream for the Homeowners and protect our Water.

    The 17 cents per kilowatt hour allows the Commercial Business owner and the Utility to make a profit.

    Commercial Ca. rates are 17 – 24 cents per kilowatt hour.

    Implementing a Residential Feed in Tariff at 13 cents per kilowatt hour for the first 2,300 MW, and then allow no more than -3 cents reduction in kilowatts per hour, for what ever the first tier Residential rate is in you area, for the remaining capacity of Residential Solar . A game changer for the Voting, Tax Paying Home Owner and a Fair Profit for The Utility, a win for our Children, Utilities, and Our Planet.

    We also need to change a current law, California law does not allow Homeowners to oversize their Renewable Energy systems.

    Campaign to allow Californian residents to sell electricity obtained by renewable energy for a fair pro-business market price. Will you read, sign, and share this petition?

    http://signon.org/sign/let-california-home-owners